Effect of SiO₂ Encapsulation on the Nitrogen Reorganization in a GaNAs/GaAs Single Quantum Well

Effects of SiO₂ encapsulation and rapid thermal annealing on the optical properties of a GaNAs/GaAs single quantum well (SQW) are studied by low-temperature photoluminescence (LTPL). After annealing at 800°C for 30 s, a blueshift of the LTPL peak energy for the SiO₂-capped region is 25 meV and that for the bare region is 0.8 meV. The results can be attributed to the nitrogen reorganization in the GaNAs/GaAs SQW. It is also shown that the nitrogen reorganization can be obviously enhanced by the SiO₂ cap-layer. A simple model is used to describe the SiO₂-enhanced blueshift of the LTPL peak energy. The estimated activation energy of the N atomic reorganization for the samples annealing with and without SiO₂ cap-layer are 2.9 eV and 3.1 eV, respectively.